Telephone system



May 23, 1939. w. PINELL 2,159,101

TELEPHONE SYSTEM Filed April 4, 1936 2 Sheets-Sheet 1 FIG. PART! Lri'n F/E i I 1' P w Sc I I Lyn-A I L P/ M We I WI' I. I I

1 N VENTOR. WALTER PIA/ELL ATTORNEY.

Patented May 23, 1939 UNITED STATES PATENT OFFICE TELEPHONE SYSTEM Application April 4, 1936, Serial No. 72,680

-In Germany May '7, 1935 10 Claims.

The present invention relates to automatically operated telephone systems.

In such systems it may be necessary, on account of the condition of the subscribers lines,

to equip the subscribers stations differently, so that subscribers stations whose lines are in a good condition are supplied with exchange battery feeding, while subscribers stations having lines possessing a high resistance of leakages are provided with local battery feeding.

The present invention aims at producing an arrangement which enables the variously equipped subscribers stations to be connected to one and the same exchange, while at the same time avoiding division of the subscribers stations into groups in the exchange according to their mode of operation.

This is achieved in that switching means are automatically operated over selectors which are set on lines leading to differently equipped subscribers stations which either set up a microphone feeding bridge or merely a signalling circuit over the speaking leads according to the equipment of the subscribers stations connected up.

The invention is represented in Fig. 1, parts I and 2, and modifications thereof are shown in Figs. 2 and 3 of the drawings, but the invention is not to be considered to be limited to these embodiments. Only those details which are necessary for understanding the invention are represented. Tnl represents a subscribers station which possesses a magneto for initiating calls. The emission of impulses on the part of this subscribers station is effected by operating a dial.

The subscriber TM is provided with a station in which the initiation of a call takes place on removing the receiver. Impulse transmission takes place as before by operating a dial. As

indicated in the drawings both subscribers have access to the repeater Uel over the call finder AS. Switching over takes place in the repeater Uel in accordance with the equipment of the subscribers station. Similar switching over takes place in the repeater U62, this adjusting itself according to the equipment of the station of the desired subscriber.

When the subscriber at the station Tnl initiates a call he operates his magneto In. Contact am is accordingly switched over so that the alternating current produced by the magneto takes the following path: earth, contact lab of a relay which is not shown, which is operated when all the call finders are engaged, winding I of relay R, contact 5t, lead L contact Zhu of the switchhook at the calling station, contact 3m, magneto In, lead Lb, contact 615 and earth. In circuit relay R energizes. Relay R operates its contacts and over contact 11 sets up the following locking circuit: earth, contact 4ab', winding I of relay R, contacts H and 8t, relay An, battery and earth. In this circuit the starting relay An is operated. Moreover, relay R on energizing prepares a testing circuit over contact 9r by connecting the winding II of relay R and the relay T to the contact bank of the call finder AS. Contact I01 is closed. By closing contact [2cm earth is connected to the starting line an! so that a free call finder is set in operation. If the call finder AS represented in the drawings is free the following circuit is established: earth, contact IZan, lead Anl, contact 1312, relay C, battery and. earth. Relay C operates and operates its contacts 14c and I50. By means of contact I40 a testing circuit is set up for the call finder passing over the wiper sc. Contact 150 causes the energization of the rotary magnet Das of the call finder AS. This energization takes place in the following circuit: earth, contacts 16p and I50, rotary magnet Das, battery and earth. The rotary magnet advances the wipers of the call finder by one step and operates the contact Ildas. Relay C is short-circuited over contact "dos and releases. Accordingly, by this opening of contact l5c the rotary magnet of the call finder is deenergized, contact l'ldas is opened whereupon relay C again energizes. This reciprocal play between the rotary magnet of the call finder and relay'C continues until the calling line has been reached.

When the calling line is reached the following testing circuit is established, earth, contact Me, windings II and I of the testing relay P, wiper sc of the call finder AS, contact 9r, winding II of relay R, the contacts I01 and l8t which are arranged in parallel, relay T, battery and earth. In this circuit relays P and T energize. By the energizing of relay P the stepping circuit of the rotary magnet Das is broken by the opening of contact 16p so that the magnet finally releases and relay C remains energized. The following locking circuit is established over contact I950: earth, contacts 20m, 1913, winding I of relay P, wiper so of the call finder AS. Over contact 2| p relay U is connected to wiper set of the call finder. Relay U is, however, not energized since no p tential is connected to the contact on which the call finder is set. The speaking leads are switched through at contacts 22p and 2311. Contact 24p causes relay V to energize, relay V energizui. and

by switching over contact I311 causes the starting line Anl to be switched over on to the line Anll,

which leads to the call initiating relay of another call finder.

Through the energizing of relay T on the testing of call finder AS the starting relay An was deenergized by the opening of contact 8t unless another call is proceeding at the same moment from any one of the group of subscribers with which relay An is associated in common. By,

the opening of contact 52? winding I of relay R is disconnected from the lead La. By the switching over of contact (it the earth is disconnected from the lead Lb. Contact l8t is opened, but this does not provoke any switching operations.

When the subscriber, after operating his magneto, takes up his receiver the switchhook contacts Ihu and Zhu are operated. Earth is hereby connected over contact lhu through the impulse contact nsi over windings I and II of the choke coil DT to the two leads of the subscribers lines. Two parallel circuits are thereby set up over the two leads of the subscribers lines and the wipers of the call finder, these passing over winding I of the transformer TTZ to battery and earth. The transformer Tr2 forms an impulse repeater over which the impulses are inductively transmitted, and operate the polarized impulse receiving relay S arranged in series with the winding II of this transformer. The transformer TT4 represents the speech repeater.

The closing of the two impulse circuits on taking up the receiver and after the call finder AS has been set causes the armature of the polarized impulse receiving relay S to be switched over. Relay J is accordingly energized in the following circuit: earth, contacts 2212i, 23p, relay J; contact 248. Relay J operates its contact 257'. This causes the energization of relay A. Relay A operates its contacts 26a and 21a and 28a.

If, now, the subscriber operates his dial, the contact nsa is permanently closed during the operation of the dial while when the dial is allowed to run back the contact 11.52 is intermittently operated. On the first opening of contact nsi winding I of the transformer T2 is influenced over both speaking leads simultaneously. The impulse receiving relay S accordingly moves its armature into the rest position. This causes the release of relay 'J. Relay J operates its contacts. Through contacts 257' relay VI is energized. Relay VI opens contacts 20M and 2201. These do not, however, involve any switching operations since the earth disconnected over contacts 20M and 220i is applied over contacts 210. and28a on account of the energizing of relay A. On the closing of the parallel circuits by the dial contact nsi the impulse receiving relay takes up its working position once more. Relay J is accordingly energized and switches over its contact257'. The impulses transmitted in this'way areused to set the final selector LW in the known manner.

When the impulse transmission is finished relay S remains in its operated position. Relay J accordingly also remains energized. Since contact 25? is switched over relay VI is caused to deenergize. Contacts 20121 and 22111 accordingly return to normal.

If the desired line is free the testing relay Pl associated with thevfinal selector energizes in the known way. This relay causes the switching through of the final selector and the transmission of ringing current in any known manner (with which the invention is not concerned). Assuming that the called subscriber has a station which of the subscriber at station Tnl.

is provided with magneto ringing and local battery feeding as is station Tnl no switching over in the repeater Ue2 takes place.

The switching operations taking place at the station of the desired subscriber, whose station is similar to Tnl, will now be explained. The ringing current transmitted to the called subscriber passes off the speaking lead Lam of the latter, the switchhook contact 27w, the contact am of the magneto In in the rest position, over the bell W and back over the lead Llm. When the subscriber takes up his receiver the switchhook contacts lhu and 27m are operated so that earth is applied simultaneously over windings I and II over the choke coil Dr to the leads La and Lb. Winding I of the transformer 'I'TS in the final selector LW is accordingly influenced. Winding II is thus inductively influence in such a manner that the relay E which is also a polarized relay is energized. relay can be used in any known manner to transmit metering impulses or to disconnect ringing current or to control any particular signals.

When the calling subscriber at station Tn! re places his receiver after setting up a call the contacts lhu and 27111. are returned to normal. The earth, which is connected to the two speaking leads is thus disconnected. Relay S returns to normal and opens the circuit relay J at contact 24s. Relay J switches over contact 257. This causes relay A to deenergize, but relay Vi, however, has previously energized. During the release period of relay A relay Vi is energized therefore. On the opening ofcontact 2911! relay P accordingly deenergizcs. Relay P operates its contacts and finally breaks the testing circuit by opening contact i929. Relay V releases and switches over contact i322. Whenrelay A falls back and VI restoresto normal the arrangement is again in the receiving condition.

The release of the final selector can take place in dependence upon the replacement of the receiver by the called party under the control of relay E or alternatively can be effected on the release of the call finder, in which case the permanent called condition existing at the called station must be rendered inoperative.

When the subscriber at the station T112 initiates a call the following circuit is setup on taking up the receiver: earth, contact 29t2, lead Lb'l, loop The calling line is characterized in the call finder by contact 33r2. Contact 341'2 starts up a free call finder by applying earth to the starting lead A'nl over contact 35t2. If the call finder AS is free the latter is started up by the aid of relay C in the same manner as has been described in the case of the initiation of the call on the part When the call finder AS reaches the line of the calling subscriber T112 the following testing circuit is set up: earth, contact I40, windings II and I of relay P, wiper so, contact 3312. winding I of relay R2, contact 3lt2, winding I of relay T2, battery and earth. The relays T2 and P energize. Relay P brings the call finder to rest in the manner already described. Relay T2 operates its contacts and at contacts 35t2 disconnects the starting impulse from the starting lead Anl. Contact 29t2 and 3M2 are switched over so that no leakage can occur from the speaking leads Lai and Lbl. Relay R2 is maintained energized over its winding I.

When the call finder AS is set on the line of the subscriber Tn2 the wiper sd of the call finder is connected to the earth potential ET. This causes relay U to be energized. Relay U effects switching over in the repeater Uel in that by operating contact 40a earth is applied to the lead passing over wiper sb of the call finder. In addition the metallic connection between the two finders of the speech repeater TM is broken. by contact 4011. and replaced by the condenser K0. Accordingly earth is connected to the speaking lead Lbl and battery to the speaking lead Lal over winding I of the transformer Tr2. In thecircuit the transformer receives an impulse on switching through which causes the polarized relay S to energize. Relay S then causes relay J to energize in the manner already described. When the subscriber at the station T112 operates his dial the loop existing at the subscribers station is interrupted. This affects the relay S in such a way that the latter changes its condition of energization at each opening and closing of the loop. In this way impulses are transmitted to the final selector LW and effects the setting of the latter.

If the final selector LW is set on a subscribers station which operates with the exchange battery feeding relay UI in the final selector energizes. Relay UI operates its contact 4lul whereby a similar switching over in the repeater Ue2 takes place as has already been described in the case of repeater Uel.

It is, of course, also possible for a subscriber having exchange battery feeding to call a subscriber with local battery feeding and vice versa.

When on terminating the call the subscriber T112 replaces his receiver relay S returns to normal. Relay J and thereupon relays A and VI deenergize. Relay P releases and promotes the release of relay U, so that the system represented may be taken into use again after relays R2 and T2 have released.

It may be mentioned that the construction of the subscribers circuit at the calling station Tn2 also allows the final selector to be released directly when the calling subscriber gives the clearing signal, in that, for example, the testing lead is opened at wiper we of the final selector. In this case the incoming lead Lcn2 of the called subscriber is opened. This has the effect, since relay T2 is constructed as a slow'-torelease relay, that relay R2 releases more quickly than does relay T2, so that the following circuit is established: earth, Winding I of relay T2, contact 32r2, winding II of relay T2, contact 30t2, loop at the subscribers station Tn2, contact 29t2, contact 3H2, and earth. In this circuit relay T2 holds up and by keeping open the contacts 35152 and 31152 prevents the establishment of the calling condition at subscriber's line of station T112.

In Fig. 2 a further embodiment is represented, which enables one wiper at the call finder and at the final selector to be dispensed with. This figure represents how the controlling relays U and UI can be operated over the testing wiper of the associated switching devices. The upper embodiment in Fig. 2 shows the wiper so of the call finder AS over which, after the testing relay P has taken place and contact p has been closed, relay U can be energized, so as to control the repeater Uel. By specially adjusting the ratio of the resistance in the testing circuits which are reached over Wiper sc the relay U may be caused to energize only when the call finder is set on the subscribers lines for which switching over is necessary. Relay Ul, Fig. 2, is operated in a manner similar to that described above.

Fig. 3 shows the controlling arrangement for the switching over relay Ul involving a cam contact (Icop) controlled by the final selector itself. The contact is operated when the final selector is set on a line necessitating a switching over in the repeater.

What is claimed is:

1. In a telephone system, common-battery subscriber lines, local-battery subscriber lines, a link for interconnecting said lines for conversation, switching means for automatically connecting said link with any one of said lines where a call is initiated thereover, a common-battery currentsupply connection and an alternative local-battery signalling connection in said link, and discriminating means in said link effective responsive to said connection of the calling line to said link and controlled through said switching means according to the character of the calling line connected to the link for determining which of said connections is effective.

2. In a telephone system, loop-signalling subscriber lines, simplex-signalling subscriber lines, a link for interconnecting said lines for conversation, switching means for connecting said link with a calling one of said lines, loop signalling connections in said link for enabling signalling to occur over loop-signalling lines, alternative simplex-signalling connections in said link to enable signalling to occur over simplex-signalling lines, and discriminating means in said link controlled through said switching means according to character of the calling line connected to the link for determining which of said connections shall be effective.

3. In a telephone system, subscriber lines having a given type of substation equipment, other subscriber lines having a different type of substation equipment, a connecting link common to all said lines and alternatively adaptable to cooperate with either class of substation equipment, switching means for automatically connecting said link to the line over which a call is initiated, and adapting means in the link automatically controlled through the switching means responsive to said connection of said line thereto for adapting the link to cooperate with the connected substation equipment according to its type.

4. In a telephone system, subscriber lines divided into classes, a conversational link comprising two sections inductively associated for the interexchange of voice currents, each section having alternative feeding paths, each path adapted for cooperation with a subscriber line of a different class, automatic switching apparatus controlled over a calling line of any class for connecting such line with the first section of said link, other switching apparatus controlled over the calling line for connecting the other end of the link to a desired called line of any class, and means at said link controlled through the said connections made thereto for securing a feeding path at each section of the link adapted for cooperating with the line connected to such section.

5. In an automatic telephone system, commonbattery loop dialling subscribers lines, local-battery simplex-dialling subscribers lines, a link for completing talking connections, means responsive to the initiation of a call over one of said lines for connecting said link with said calling line, a pair of circuits in said link, each adapted to cooperate with only one of said types of subscribers lines, and means in said link for connecting to the calling line the circuit adapted to cooperate with the type of calling line con-' nected to the link.

6. In an automatic telephone system, commonbattery loop-dialling subscribers lines, local-battery simplex dialling subscribers lines, a link for completing talking connections between any of said lines, means in said link controlled responsive to the connection of a calling line to said link for altering the calling end of the link circuit to correspond to the type of circuit of the calling line, and means in said link controlled responsive to the establishment of a connection with a called subscribers line vfor altering the called end of the link circuit tocorrespond to the type of circuit of the called line.

'7. In an automatic telephone system, subscribers lines for substations having a given type of circuit, other subscribers lines for substations having a different type of circuit, a link for completing talking connections between any of said lines, means in said link controlled responsive to the connection of a calling line to said link for adapting the calling end of the link circuit to cooperate with the type of circuit at the calling substation, and means in said link controlled responsive to the establishment of a connection with a called subscribers line for adapting the called end of the link circuit to cooperate with the type of circuit at the called substation.

8. In a signalling system, an automatic switch, lines accessible to said switch, means for associating said switch with any one of said lines, signal receiving means in said switch, and discriminating means in said switch operated at times to cause said signal receiving means to be controlled by signalling over one conductor of said line alone and operated at other times to cause said signal receiving means to be controlled by signalling over a plurality of conductors of said line connected in parallel.

9. In a telephone system, an automatic switch, lines accessible to said switch over its wipers, means for causing said wipers to be associated with any one of said lines, a pair of alternative signal receiving circuits in said switch, and discriminating means in said switch effective responsive to the association of said wipers with said line for determining which of said circuits shall be placed under the influence of said line.

10. In a telephone system,-an automatic switch, lines accessible to said switch over its wipers, means for causing said wipers to be associated with any one of said lines, a. pair of alternative voice transmission circuits in said switch, and discriminating means in said switch effective responsive to the association of said wipers with said lines for determining which of said circuits shall be connected to said lines.

WALTER PINELL. 

